We present in this work a study of the strategy of reproduction adopted by Synodus saurus (Linné, 1758), only representative of the family of Synodontidae on Tunisian coasts. It is based on several parameters: the sex ratio is balanced in periods of laying and of maturation. The age of the first sexual maturity is valued to 2 years for the males and to 3 years for the females with respective sizes of 144 and 212 mm. The spawning is sequential and occurs from June to October. The hepatic and somatic reserves are mobilized to gonadic metabolism during the laying period, this is translated by a fall of hepatosomatic and a decrease of weight during the production and the emission of sexual products. The ovocytes are numerous and small and the potential fecundity per spawning is included between 2,000 and 100,000 according to the size of the females.